/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Operations/IntrinsicTriangulationMesh.h
Split an intrinsic edge of the mesh by inserting a vertex. This creates a new triangle on either side of the edge (ie a 2-4 split). If the original edge had vertices [a,b], with triangles t0=[a,b,c] and t1=[b,a,d], then the split inserts new vertex f. After the split t0=[a,f,c] and t1=[f,a,d], and we have t2=[f,b,c] and t3=[f,d,b] (it's best to draw it out on paper...) SplitInfo.OriginalTriangles = {t0, t1} and SplitInfo.NewTriangles = {t2, t3}
Ok on success, or enum value indicates why operation cannot be applied. Mesh remains unmodified on error.
[EMeshResult](API\Runtime\GeometryCore\UE__Geometry__EMeshResult) SplitEdge ( int32 EdgeAB, [FEdgeSplitInfo](API\Plugins\DynamicMesh\Operations\FSimpleIntrinsicMesh\FEdgeSplitInfo) & SplitInfo, double SplitParameterT )